New: C-Menu FAQ

New: C-Menu User Guide

New: Augmenting C-Menu

New: C-Menu API

New: Configuration Snippets

Table of Contents

• C-Menu Menu, Form, Pick, View, RSH, and C-Keys
  • C-Menu Menu
  • C-Menu C-Keys - Diagnose Keyboard/Mouse Input
  • C-Menu Pick - A Picker
  • C-Menu Form for Data Entry and Editing
  • C-Menu Form Key Features
  • C-Menu Form Data Types
  • C-Menu Sample Menu Description File
  • C-Menu View
    • Log File With Editor
    • Screenshot of the Same File With C-Menu View
  • C-Menu View and Color Manual Pages
  • Example Manual Page Using Editor
  • Example C-Menu Manual Page
  • Demand Paged Virtual Address Space
  • C-Menu View - Other Features
  • C-Menu 3-Channel Gamma Correction
• RSH
  • Maintaining Security with RSH
• C-Menu Features
• C-Menu Configuration
• C-Menu Installation
• MIT License

C-Menu Menu, Form, Pick, View, RSH, and C-Keys

C-Menu is a lightweight, flexible, and easy-to-use suite of programs for creating a sophisticated user interface for your applications. Menus, Form, Pick, and View, using a classical text-based terminal interface(TUI) for applications running on Linux and Unix-like operating systems. C-Menu is designed to be simple to use while providing powerful features to implement menu driven frameworks for applications.

This is a real TUI. No GUI libraries, no X11, no Wayland, no dependencies on bloated toolkits. Just good old-fashioned text mode, using NCurses for terminal handling.

While C-Menu does support mouse input, the primary mode of operation is keyboard driven, as God intended. You can navigate menus, fill out forms, and pick items using only the keyboard. This makes C-Menu ideal for use in terminal environments where mouse input may not be available or practical.

C-Menu Menu

At the top of the stack is C-Menu Menu, which reads a simple description file like the one below and displays a colorful and easy-to -follow menu to the user. When the user selects an item, with either keyboard or mouse, C-Menu executes the corresponding command. It’s like writing shell scripts, but with a snazzy menu interface.

From the above examples, you can get an idea of how C-Menu works. Examine line-21 in “main.m” above. C-Menu Menu starts C-Menu View, which in turn executes “tree-sitter highlight view_engine.c”. Tree -Sitter doesn’t need to know anything about C-Menu View. It just sends output to it’s standard output device, which happens to be a pipe into C-Menu View’s receiver. C-Menu View maps Tree-Sitter’s output to the Kernel’s demand paged virtual memory and you get:

C-Menu C-Keys - Diagnose Keyboard/Mouse Input

With C-Menu C-Keys, you can diagnose and resolve keyboard and mouse issues quickly and easily. Just press a key and get the Octal, Decimal, Hexadecimal, the Escape Sequence Binding, and the NCurses Identifier. It’s definitely easier than rummaging through hardware documentation and NCurses header files. It’s also a good way to identify which keys are reserved by your terminal emulator, and gives you the specific key codes so you can easily add your own Extended NCurses keys.

C-Menu C-Keys also provides diagnostics for mouse actions and geometry.

Just add hot water, stir, and Bob’s your uncle, you have soup! 😀

C-Menu Pick - A Picker

C-Menu Pick provides a list of objects from arguments, piped input, or a text file. The user selects an object by using cursor movement keys, up, down, left, right, page-up, or page-down and pressing the space bar. Alternatively, the user can use the mouse and click on the object. When finished selecting objects, the user presses the Enter or F(10) key. If the “number_of_selections” variable is set to 1 (one), Pick will assume the user is finished and perform the specified action. Output can be piped to standard output, or provided as arguments to an executable file specified in the description file.

Here’s a simple way to use C-Menu Pick:

Pick a file to view using “lf”, a utility to search for files using regular expressions, and which is included with C-Menu:

view -S "lf -r . .*\.c$"

Execute a program or script on a picked file:

pick -S "lf -r . .*\.c$" -n 1 -c my_executable

Note that the syntax for “lf” (list files) is not similar to Unix “ls”.

The usage of “lf” is:

lf directory regular_expression

If you type “lf *.c”, it will fail for lack of a valid regular expression. That’s because “ls” uses shell expansion, while “lf” uses regular expressions. Find supports regular expressions, but such a comprehensive program carries a penalty in size and overhead. “lf” is

streamlined to provide input for a picker.

find -regex '.*\.c$' | sed 's/^..//'

lf . '.*\.c$'

C-Menu Form for Data Entry and Editing

FORM is a lightweight and flexible form handling library designed to simplify the process of creating, validating, and managing forms.

It provides a straightforward API for defining form fields, handling user input, and performing validation checks.

C-Menu Form Key Features

• Easy Form Creation: Define forms with various field types such as text, number, email, and more.
• Validation: Built-in validation rules to ensure data integrity, including required fields, format checks, and custom validators.
• User Input Handling: Seamlessly capture and process user input from the command line or text-based interfaces.
• Customizable: Extendable architecture allowing developers to create custom field types and validation rules.
• Integration: Designed to work well with other components of the C -Menu Project, enabling a cohesive development experience.

C-Menu Form Data Types

FORM displays data entry forms based on a description file. It allows users to input data in a structured manner. The entered data can then be processed by a specified command or script. Internally, the numeric entries are converted to binary integer, long, float, or double.

The two Cash Receipts entry forms above are identical except the top form has field brackets turned on and the bottom form has fill characters set to underscore. This is a simple configuration option from the command line or the configuration file.

If you make a mistake, in the form description syntax, as I did below, you will get a notification pinpointing the problem. In this message, we can see that the format field on line 3 of “receipt.f” is invalid.

I have a “3”, and it should have been “String”. The corrected line would be: “F!2!18!10!String”.

Need quick and easy Cash Receipts, General Journal, or wedding invitation list? FORM has you covered. The application shown above took about 10 minutes from design to test. It doesn’t post transactions, or keep running balances yet, but that’s why we have people like you.

FORM also makes a great front-end for SQL database queries.

C-Menu Sample Menu Description File

As you can see, the description file is straightforward and easy to read. Each menu item consists of a label and a command to execute. The label is displayed in the menu, and the command is executed when the user selects that item.

Here’s just one example of how easy it is to create useful programs with the C-Menu Form facility.

We hope you find C-Menu useful for your projects. It’s a powerful tool that can greatly simplify the process of creating text-based user interfaces for your applications.

C-Menu View

VIEW is an easy-to-use text file viewer that allows users to view text files in a terminal environment. It supports basic navigation, regular expression search functionality, horizontal scrolling, ANSI escape highlighting, Unicode, and NCurses wide characters. VIEW can be invoked from within MENU, FORM, or PICK to provide contextual help or stand -alone, full-screen as a system pager.

Log File With Editor

Screenshot of the Same File With C-Menu View

One especially useful feature of C-Menu View is its incredible speed with large text files, like system logs. C-Menu View can open and display multi-gigabyte text files almost instantaneously. Seek from beginning to end of a 1 gigabyte file takes a few milliseconds.

C-Menu View and Color Manual Pages

C-Menu View can also be used as a pager for manual pages. By setting the “MANPAGER” environment variable to “view”, users can enjoy the benefits of C-Menu View’s features while reading manual pages.

To use C-Menu View as your system pager, add the following line to your shell configuration file (e.g., .bashrc or .zshrc):

export PAGER="view"

You can also filter manual pages through ~/menuapp/msrc/man.sed to colorize underlined emboldened, and italicized text. This sed script is included with C-Menu. To use it, you can run the following command in your terminal:

man -Tutf8 bash.ls | sed -f ~/menuapp/msrc/man.sed | view

Example Manual Page Using Editor

Example C-Menu Manual Page

Demand Paged Virtual Address Space

• C-Menu View doesn’t employ seek and read operations in a complicated buffering scheme. There is a better way.
• C-Menu View accesses files as arrays, using the Kernel’s sophisticated demand paged virtual memory.
• Lazy loading means that C-Menu View doesn’t waste time seeking, reading, and populating buffers that will never be used.
• Zero-Copy I-O - Conventional programs copy file buffers into heap address space. C-Menu View bypasses that step and reads directly from the Kernel’s virtual memory.
• Simplicity - C-Menu View has no reads, no seeks, no complicated buffer management schemes, not for view. The following snippet includes

“all” of View’s file I-O on lines 22 and 12.

In technical parlance, I’ll explain precisely how it works. See if you can follow me. 😁

C-Menu View’s File I-O subsystem does three things:

• Get the next byte,
• Get the previous byte, or
• Get a byte from a specified position

C-Menu View is blazingly fast because it leverages the Kernel’s demand paged virtual memory system. When a file is opened, C-Menu View maps the file into the process’s virtual address space using the mmap system call. Zero-copy I-O is achieved by mapping the file directly from kernel address space.

When C-Menu View needs to access a byte at a specific position, it simply calculates the corresponding memory address based on the file offset and reads the byte directly from that address. If the required page is not already in memory, the Kernel automatically handles the page fault by loading the necessary data from the file into memory. This approach eliminates the need for explicit read and seek operations, and copying data to the processes memory, resulting in faster access times and reduced overhead.

C-Menu View - Other Features

Horizontal scrolling for long lines. C-Menu View writes output to a virtual screen, a Ncurses pad, to accommodate lines longer than the physical screen.

C-Menu View has full support for Unicode, translating ASCII text and multi-byte-sequences to wide characters (wchar_t), and wide characters and ANSI SGR sequences to complex characters (cchar_t). The complex characters combine displayable characters plus attributes, such as bold, italic, underline, reverse, and foreground and background colors. NCurses can display more than 16 million colors.

C-Menu View supports mouse wheel vertical scrolling.

C-Menu 3-Channel Gamma Correction

When using utilities such as “tree-sitter highlighter”, “pygmentize”, or “bat” to highlight files, the text is sometimes almost unreadable. On the left-hand side of the following screenshot, “less” does a great job of rendering the output of pygmentize, but C-Menu with gamma correction can do better. It’s all about perceptual luminosity. Either from the command line or the minitrc file, the user can specify a gamma correction value for each of the three color channels, red, green, and blue. It’s a minor thing, really, but we programmers aren’t “automatons” A pleasing visual appearance makes work funner.

In the right-hand image below, gamma has been increased for red, green, and blue.

In the image below, gray gamma is used to make comments more visible. Gray gamma, as you might guess, applies to shades of gray, colors in which red, green, and blue components are of equal value.

Bezold-Brücke hue shift Web Content Accessibility Guidelines (WCAG) 2.2

• That’s a Bobby Dazzler

(Australian TV show)

With Unicode glyphs, ANSI escape highlighting, and 3-Channel gamma correction, your application is bound to Wow your clients. Nobody wants an ugly program. Of course, beauty is in the eye of the beholder. That’s why we give you control.

RSH

Despite its name, RSH is not a shell. It is a shell runner, which allows you to specify your shell of choice, and provides a consistent environment for running shell scripts and commands. RSH was designed to be invoked from within MENU, FORM, or PICK to execute commands that require elevated privileges, but its functionality extends beyond that.

You can execute commands in either user or root mode, making it a versatile tool for developing application front-ends. RSH ensures that your scripts and executables run in a controlled environment, reducing the chances of unexpected behavior due to differing shell environments. RSH forks and waits for its spawn to complete before returning control to the calling program. When executed under C-Menu’s signal handler, it catches and displays the exit status of the command, allowing for better error handling. Instead of using su -c or sudo to run commands as root, you can use rsh -c to achieve the same result in a more streamlined manner. You can literally have root access within a fraction of a second, making it ideal for work that requires frequent switching between user and root modes for various administrative tasks.

Many system administrators and developers find RSH invaluable for tasks that require elevated privileges. RSH eliminates the need to repeatedly enter passwords or switch users, streamlining workflows and improving efficiency. We all know it’s not a good idea to run everything as root, but sometimes a user want’s to avoid precious seconds it takes to enter passwords for su. With RSH, it takes three keystrokes to enter root mode and two keystrokes to get out.

Maintaining Security with RSH

Here’s an example of the proper way to use RSH.

1. Type “xx” to assume root privileges.
2. Type “make install”
3. Type “x” to relinquish root privileges.

Notice that the bash prompt changes from green to red as a reminder that you are wielding a loaded gun with the safety off. In this state, it only takes a minor typo. You mean to type “rm -r tmp/*”, but inadvertently put an extra space after tmp. I can’t even type the resulting expression.

rm -r tmp/*

Be very careful when using RSH in setuid root mode. Keep the executable protected in your home directory with appropriate permissions to prevent promiscuous access by unauthorized users. RSH should be provided only to trusted users who understand the implications of executing commands with elevated privileges. Used inappropriately, it can lead to system instability or security vulnerabilities.

RSH is as safe or unsafe as we choose to make it. It requires root access to install, and the installer should make sure it cannot be used by other users. If you are reading this, you know how to do that. Please use it responsibly.

You will notice that the build was completed under normal user privileges. Only the install portion required root access. We typed “xx” to assume root privileges, installed the package, and then immediately reverted to normal user access by typing “x”.

C-Menu Features

Create and manage multiple menus, forms, and pickers

Define interfaces using simple configuration files

Perfect for shell scripting, command-line, and terminal based applications

Made for Linux and Unix-like operating systems

Blazingly fast, even on older hardware

Text-based user interface (TUI) using ncurses

Easily customize menu options and actions

Any level of sub-menus

Navigation using keyboard inputs the way God intended

Configurable appearance and behavior

Cross-platform compatibility

MIT License - Open-source and free to use

C-Menu Configuration

User’s can have multiple runtime configurations. In the snippet above, the standard ISO 6429 / ECMA-48 colors have been redefined and orange has been added.

C-Menu Installation

To install C-Menu, simply download the source code from the repository and follow the installation instructions provided in the C-Menu User’s Guide.

MIT License

MIT License

Copyright (c) 2025 William Dudley (Bill) Waller

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.